Orthoester stabilized polyvinyl chloride resins



United States Patent 3,518,227 ORTHOESTER STABILIZED POLYVINYL CHLORIDERESINS Louis L. Wood, Washington, D.C., assignor to W. R. Grace & Co.,New York, N.Y., a corporation of Connecticut N 0 Drawing. Originalapplication Dec. 12, 1966, Ser. No. 612,066. Divided and thisapplication May 22, 1968, Ser. No. 750,689

Int. Cl. C08f 45/58 US. Cl. 260-4535 6 Claims ABSTRACT OF THE DISCLOSUREPolyvinyl chloride resins can be thermally stabilized by the addition ofan orthoester compound having the formula:

wherein R is selected from the group consisting of hydrogen, alkyl,phenyl, phenylalkyl, alkylphenylalkyl, halophenyl, nitrophenyl andalkenyl; R and R are selected from the group consisting of alkyl,phenyl, phenylalkyl, alkylphenyl and alkylphenylalkyl; and R is selectedfrom the group consisting of alkylene, phenylene, alkyl, alkylene,alkenylene, alkenylalkoxyalkyl alkylene, and alkynyne; and n has a valueof from 1 to 4. An addition of a polyhydric alcohol will generallyfurther increase the thermal stability.

The present invention is a division of my application 612,066, filedDec. 12, 1966 now abandoned, which in turn is a continuation-in-part ofmy earlier filed applications, Ser. Nos. 403,353, filed Oct. 12, 1964now abandoned and 499,093, filed Oct. 20, 1965 now abandoned.

The present invention relates to the stabilization of resins, and morespecifically to a novel stabilization agent for stabilizing vinylchloride polymers and copolymers against the degradation effects ofelevated temperatures.

It is well known that vinyl chloride containing resins degrade atelevated temperatures. When vinyl chloride polymers and copolymers aresubjected to molding temperatures in excess of about 150 C. they tend todiscolor. Serious discoloration occurs even in the relatively shortperiod of time required for a molding operation.

To date, numerous stabilizers have been suggested for use in vinylchloride type resins. The most satisfactory of these stabilizerscomprise tin, lead and cadium containing compounds. These compounds,while performing satisfactorily where toxicity is not a problem, can notbe used where the treated polymer is to come into contact withfoodstuffs and the like.

As of present, a highly effective polyvinyl chloride stabilizer whichdoes not possess toxic characteristics or propensities has not beendeveloped.

It is therefore an object of the present invention to provide a novelclass of polyvinyl chloride stabilizers.

It is another object to provide novel stabilizers for polyvinyl chloridecontaining resins which substantially enhance thermal stability of saidresins.

It is a further object to provide a class of polyvinyl chloridestabilizers which are non-toxic and may be used in resinswhich are usedin the packaging of foodstuff materials.

These and still further objects of the present invention will becomereadily apparent to one skilled in the art from the following detaileddescription and specific examples.

3,518,227 Patented June 30, 1970 ice wherein the indicated unsatisfiedwalences are occupied by hydrogen or organic radicals. It is alsocontemplated that these orthoesters may be effectively combined withpolyhydric alcohols to give a superior degree of stabilization.

More specifically, I have found that if from about 1% to about 10% byweight of a compound containing an ortho ester grouping is admixed withpolyvinyl chloride, the ortho ester compound will stabilize thepolyvinyl chloride towards heat induced degradation. Furthermore, thisstabilization effect may be enhanced by the addition of polyhydricalcohols.

The ortho esters used in the practice of the present invention may bebroadly defined as those ortho esters which possess at least one of theabove defined ortho ester groups, and which are compatible with thepolyvinyl chloride resins at the processing temperatures indicated. Bythe term compatible it is meant that the ortho ester used shouldhomogenously blend with the polyvinyl chloride and should have arelatively low vapor pressure at processing temperatures so as not tocause excessive forming of the resins at the processing temperaturesencountered.

Typical structures of suitable ortho esters which may be used in thepractice of my invention are:

R-C-ORa wherein R may represent hydrogen, alkyl, phenyl, phenylalkyl,alkylphenylalkyl, halophenyl, nitrophenyl and alkenyl; R R R may bealkyl, phenyl, phenyl-alkyl, alkylphenyl, and alkylphenyl-alkyl whereinR R and R has the meaning given in (1) above; R may be alkylene,phenylene, and alkylphenylene; and X represents oxygen and sulfur.

wherein R, R and R have the meaning given above (1); R may be alkylene,phenylene, alkyalkylene, alkenylene, alkenylalkoxy alkylalkylene andalkynylene; and n has a value of from 1 to 4.

wherein R and R have the meaning given in (1) above;

and R may be alkylene, alkylalkylene, and alkenylwherein R has themeaning alkylene.

The reaction products of lower orthoesters such as triethyl orthoacetateand triethylorthoformate with polyols given above and R is such asglycerol, sorbitol, and mannitol yield complex esterified, products.

Specific examples of orthoejsterswhich may be used in the presentinvention along with a general description of how the orthoestercompound maybe prepared'aregiven in the following paragraphs. (Thenumeral designations will be used in the subsequent specific examplesand claims to identify these compounds.) I p The following three methodsmay be used'to prepare the following orthoesters:

(A) Iminoester route, as set forth in Pinner, Ber., 16 356, 1644 (1883).

The appropriate nitriles are reacted with one equivalent of dry hydrogenchloride and one equivalent of alcohol to form an iminoesterhydrochloride which is then alcoholyzed with an excess of alcohol toform the orthoester. The reaction may be outlined as follows:

RON ROH HCl excess ROH RCOR-; RC(OR)2 NHtCl NH2G1 A dinitrile can beused as follows:

NGRCN ZROH 2HC1 NHzCl NH2C1 excess a OH RO -R-OoR' (RO);CRC(0R)3 2NH4C1Furthermore, diols may be used at either one or both steps of thesynthesis.

' 1| IH2Cl 16111201 2RCN HOROH 21101 ROROCR (B) Exchange reaction asdescribed by Mkhitaryan,

V. J. Gen. Chem. (USSR) 8 1361 (1938).

The alkoxy groups of a readily available orthoester such as triethylorthoacetate or formate are displaced by a higher boiling alcohol orpolyol as follows:

When more complex polyols including triols through -hexols are used,many complex polymeric products are possible. However, these reactionproducts are formed by continuing the reaction until the requiredamounts of lower alcohol has been removed. That is the exchanye reactionis continued until the calculated amount of lower alcohol is displacedby the higher alcohols.

(C) Alcoholysis of triholomethyl groups as set forth by Sah, P. and Ma,S.T., J. Am. Che. Soc. 54 2964 (1932).

The appropriately substituted trichloromethyl compound is treated with ametal alkoxide.

This compound is conveniently prepared by routes A or B.

This compound is prepared by routes A or' B.

VIII.

CzHaGHzO CH2CH=CH2 This compound is prepared by route B.

IX 7 (CH CH CH O) C%CH C(OCH CH CH This compound is prepared by routes Aor B.

oHa0 0oH2o oH2) 3 This compound is prepared by route B.

H, CH3 OH: OH:

This compound is prepared by routes A and B.

/H3C\ /0-CH2 CHaCH2- O OH 0 OCHCHz/ (XII) CH C(0C H This compound isprepared by route A. (XIII) (CH O C-CH CH SCH CH C OCH 3 This compoundis prepared by route A. (XIV) (C H O) CCI-I -CH SCH CH C (OC H 3 Thiscompound is prepared by route A. (XV) (CH O) CCH CH OCH CH C(OCH Thiscompound is prepared by route A. a( 2)10 3)a This compound is preparedby route A.

XVII.

This compound is prepared by route C. (XVIII) 0H30 0 CHz(CH2)sCHa)2 Thiscompound is prepared by route A. 3 )3 z)4 3)a This compound is preparedby route A.

This compound is prepared by route A.

(XXI) O C2H5 02135 O C2115 CHZ- OCHzC--O-CCHa O C2115 O C2H5CHzOCH2CH=CHz This compound is prepared by route B. (XXII) OHz-CH2 CH2CH2 0 5 5 CHa COCH2CH2O CGHa This compound is prepared by route B.(XXIII) (32H:

H--O C2115 This. compound may be prepared by routes A, B, or C.

(XXIV) CH3 CH5 CH3 CH:

C \CH2 C CHz t) 6 o 0 CHa C 0CH2CH20 CCHz This compound may be preparedby route B.

This compound was prepared by route B.

This compound was prepared by route B.

(XXVII) Poly(glyceryl orthoformate) This compound was prepared by way ofroute B using one mole of triethyl orthoacetate and one mole ofglycerol.

(XXVIII) Poly(sorbityl orthoacetate) This compound was prepared by routeB from 2 moles of triethyl orthoacetate and one mole of sorbitol.

(XXIX) Poly(mannityl orthoacetate) This compound was prepared by route Busing 2 moles of trietyl orthoacetate and one mole mannitol.

The effectiveness of the present orthoester stabilizers may be enhancedby adding thereto from about 0.1 to about 10 moles of a high boilingalcohol per mole of orthoester.

Typical alcohols which may be added possess the general structure R(OH)wherein R1 is an organic radical and x has a value of from 1 to 6.Preferably these alcohols have a boiling point in excess of about 175 C.

In the above formula R may be alkyl, alkylphenyl, phenylalkyl, alkylene,phenylene, polyalkoxyalkylene and trivalent counterparts thereof.Typical polyhydric alcohols useful in the practice of the presentinvention are 0, m, p-Xylene, a,a-diol, trimethylolpropane monopropylether, trimethylolpropane monoallyl ether, propylene glycol, diethyleneglycol, dimethyloctadiynediol, pentaerythritol, trimethylolpropane,neopentylglycol, benzylalcohol, cetyl acohol and dipentaerythritol.

Polyvinyl chlorides which are treated in accordance with the practice ofmy present invention are those vinyl chloride polymers and vinylchloride copolymers having a number average molecular weight from about10,000 to about 150,000 and a weight average molecular weight of fromabout 20,000 to 1,000,000. These vinyl chloride polymers and copolymersare well known to those skilled in the art and comprise vinyl chloridehomopolymers as The stabilization agents, namely the ortho esterscontemplated herein, are incorporated with the vinyl chloride polymerand copolymers by any conventional means. The blending may beconveniently carried out first preparing a slurry of finely dividedpolymer in a solvent for the ortho ester such as methanol, acetone,ethyl ether. The solution is then separated from the slurry and thepolymer particles are dried. This results in polymer particles which arethoroughly coated with the ortho esters set forth herein. It is alsocontemplated that the blending may be achieved by milling the polymer atthe softening temperatures therefor until an intimate blend of thestabilization agent with the polymer is achieved. Milling is generallyconducted atconventional temperatures of to 200 C. for a period of timesulficient to obtain thorough blending of the stabilization agent withthe polymer.

The stabilized vinyl chloride polymers and copolymers contemplatedherein may be used in the formation of rigid polyvinyl chloride moldedarticles. These rigid moldedpieces are formed in extrusion and injectionmolding devices which are well known to those skilled in the art andwhich operate in the neighborhood of 150 to 200 C. The stabilizationagents contemplated herein effectively stabilize the vinyl chloridepolymer and copolymer during the molding process and make it possible toproduce rigid moldings having a low degree of color I change and goodclarity.

It is also contemplated that the polyvinyl chloride resins stabilized bythe present stabilizers may be admixed with various plasticizers such ashigh boiling esters including the alkyl phthalates, phosphates,adipates, sebacates, azelates, and various polymeric type esterplasticizers Also the present composition may contain other additivessuch as Zn, Mg, Sn and Ca salts of carboxylic acids, and phosphateesters. Furthermore, the resins may be included in plastisol typepreparations which are fabricated by dipping and deposit type moldingtechniques.

Having described the basic aspects of my present invention the followingspecific examples are given to illustrate embodiments thereof.

EXAMPLE I In the examples tabulated below 9.5 g. portions of powderedVygen 120, a high molecular weight polyvinyl chloride resin, wasslurried in solutions which comprised 20 ml. of methanol and 0.5 g. ofthe various stabilizer compounds listed below. The resultant slurrieswere evaporated to dryness with constant agitation at from 40 to 60 C.and under 60 mm. Hg pressure. 3.5 g. of the polyvinyl chloride mixtureswere then pressed into plaques which measured 1 x 3" and 5 mils inthickness on a press heated to 200 C. and exerting 10,000 p.s.i. for thetimes listed in the table below. The color of the resultant plaques weremeasured by comparison with the standard Gardner color developed in theplaque the ore' efiective is the stabilizer.

Gardner color index at various times (minutes) Run Stabilizer 2 5 10 15XIV 2. 0 2. 25 2. 5 2. 5

VII 3.0 3.0 3.0 3.0

. Dibutyl tin dilaurate. 7 11 15 15 None 15 15 H 15 15 Examples 1 and 2containing the ortho esters contemplated herein-are effectivelystabilized. Example 3 which contained the well known stabilizerdibutyltin dilaurate rapidly discolored under the same conditions as didExample 4 which contained no stabilizer.

EXAMPLE I-I v In the following runs particulate polyvinyl chloridehaving a number average molecular weight of about 38,000 was dry blendedwith various amounts of orthoester and/ or polyhydric alcohol. Thesesamples were then placed in the mixing chamber of a BrabenderPlastographv at 190 C. and open to the air. A roller speed of r.p.m. wasused to knead the polymer formulations. The Brabender Plastographcontinuously records the torque required to knead the mass. From thetorque values one can determine:

-(a) The time required for the powder mixture to fuse into a workableplastic mass (flux time) (b) The force required to work the plastic mass(average torque value) (c) The onset of crosslinking (decompositiontime).

The actual temperature of the plastic mass was also continuouslymeasured. Small samples of the polymers were also removed periodicallyfrom the mixing chamber and their color compared to those of thestandard Gardner color scale (0.0=colorless to 5.0=dar-k amber). Theless 40 scale.

TABLE 11 Decomposition Coneentime tration, Flux after Polymer Color(Gardner scale: 0=eolorless; 15=br0wn Stabilizer (numerals referorthoparts per time, flux Torque, (tamp I I Run ester describedpreviously) hundred mm. min. kg. 0.) 2mm. 4mm. 10 mm. 15 mm. 20 min.

1... v 5.0 2.0 v 20.0 1.25 199-204 1.5 1.9 1.5 1.5 1.5 {g y gg 1. 520.0 1. 25 193-199 0. 2 0.2 0.5 1.0 1. 2 y a 2.0 v 17.0 1.3 195-208 1.01.0 1.0 1.5 4 x 3 3} 1.5 22.0 1.1 190-195 1.5 1.5 1.5 I m-Xylened,a-diol 2.0 3.5 10-13.5 1.9-1.5 190-210 1.5 15 Black p-Xylene a,u.'di0l2.0 3.5 3. 0-s.0 1.9-1.7 190-210 1.5 15 Black i -X 0555 5 .241101. 2.53.5 1.9-1.7 190-199 15 Black s -{T1g 12 lii1%gr5bam monoallyl 210} 1.534.0 1.4-1.2 190-197 1.0 2.0 2.0 2.0 2.0

8 81 9 MFA: 2.0 1.0 3.0 1.9-2.2 -194 Black 5.0 2.0 14.5 1.3-1.4 190-2037 1.5 3:3} 2.0 12.5 1.4 190-200 1.0 g-g 2.5 17.0 1.9-2.0 190-202 1.0 5.0v 2.0} 3.0 25.0 1.3-1.4 194-207 1.5 1.5 2.0 2.0 2.0 5.0 2.5 19 1.4194-207 2.0 2.0 2.0 1.8 Black 2:3} 2.0 27 1.1 190-198 1.5 1.5 1.5 1.51.5 3-3} 2.0 v 31 1.1 190-190 1.0 1.0 1.5 2.0 12.5 5. 0 2. 0 11. 5 1.1-1. 4 190-199 2. 0 3. 0 10 2.5 15.5 1.1-1.4 188-196 g 1.0 2.0 5.0 10.05. 0 2. 0 7. 5 1. 4 1911-199 5. 0 9. 0 8.5 1. 4 150-192 5. 0 2. 0 12.0 1. 4-1. 5 190-214 5. 0 2. 0 s. 5 1. 4 139-190 5. 0 1. 0 9. 5 1. 2-1. s-197 5. 0 1. 0 1 1221 1. 15-1. 8 191-210 5.0 20 1.0 22.0 1.3-1.8 178-2005.0

25 OH3OH3C(CH5OH)9 2.0 1.0 25.5 1.1-1.8 180-200 0.7 0.7 0.7 0.7 0.7

01130 GHQCHa-CH;

Decomposition Concentime tration, Flux alter Polymer Stabilizer(numerals refer orthoparts 'per tinge, flux Torque, (tenip., Run esterdescribed previously) hundred mm. min. kg.

00000000000000000000000000000000000 5i2RmaZ5.a2irm5255255LL5Z23Z22235432L LLL L1 .11]. ll. 11.00000000000000000000005005005005 mm54am2L1Lnm223w-m52555 552052052052050Stearie acid Black at 75min.

Greater than black.

5 3.0 after 25 min. 3.5 after min.

I claim:

g and having the C., wherein -R is an organic radical and x 1. Athermally stabilized polyvinyl chloride resin composition comprisingpolyvinyl chloride and a compound of the formula r .w s e .m H 0 m a a S5 H m me .e C O C h W 0 1 .m .a a 6.... E. M 1 n o O C m O C .mfiT. M310 H Pl mu C ewm .m 0 am v a m S 3 S a h .m 5 6 J mo clom n 0. R J m nwom R r e 9 m h n o m 0 S 5 cl 0 m n m m m d C 0 lo a O C O h w 0 1 A. .mm a c a I 8 m o m 0 m 1 n C C m .w O C O .hl h s w H u 0 m 0 o m is a hwherein R is selected from the group consisting of hydrogen, alkyl,phenyl, phenylalkyl, alkylphenylalkyl, halophenyl, nitrophenyl, and'alkenyl; R and R are selected from the group consisting of alkylphenyl, phenylalkyl, alkylphenyl and alkylphenylalkyl; and R is selectedfrom the group consisting of alkylene, phenylene, alkyl alkylone,alkenylene, alkenylalkoxyalkyl alkylene, and alknylone; and n has avalue of from 1 to 4.

References Cited UNiTEb STATES PATENTg {782,191 4/1957 Wilson 260-4535XR 11 5. The cprr' iposition of claim 1 wherein said orthoester I hasthe Formula III M M w m "j I OCzH; OCaHu 6. The comp'sition of claim 1wherein said ort hoester 1 I- Assistant Examiner has the FOImuIa'XXII002m 02H- ocamp a I v 2;. 1 us. e1. X.R. CHr-I-OCHr -oc-cH, ,g 9 45-85OCzHa CzHa mo cmcn=bm

